The IBM 2321 Data Cell announced in April 1964 (withdrawn January 1975) is a discontinued

direct access storage device A direct-access storage device (DASD) (pronounced ) is a secondary storage device in which "each physical record has a discrete location and a unique address". The term was coined by IBM to describe devices that allowed random access to data, ...

(DASD) for the IBM

System/360 The IBM System/360 (S/360) is a family of mainframe computer systems that was announced by IBM on April 7, 1964, and delivered between 1965 and 1978. It was the first family of computers designed to cover both commercial and scientific applic ...

. It holds up to 400 megabytes of data, with an access time of 95 milliseconds to 600 milliseconds, depending on the addressed strip position and data arrangement in each data cell. The 2321 was whimsically known as the "noodle picker" since the removable magnetic strips were flexible and resembled

lasagna Lasagna (, also , also known as lasagne, ) is a type of pasta, possibly one of the oldest types, made of very wide, flat sheets. Either term can also refer to an Italian dish made of stacked layers of lasagna alternating with fillings such a ...

noodles.

Characteristics

The 2321 houses up to ten removable and interchangeable ''data cells'', each containing 40 megabytes. Each data cell contains 200 strips of

magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use mag ...

, which are the basic recording media. Strips are wide and long. The total storage capacity is 400 megabytes or 800 million decimal digits. Up to eight 2321s can be attached to the IBM 2841 Control Unit, allowing an overall capacity of over three GB.IBM System Reference Library, IBM System/360 Component Descriptions, Form A26-5988 In comparison to the contemporary IBM 2311 Disk Device, the IBM 2321 Data Cell Device holds 55 times more data, while being only seven times slower (85ms and 600ms access times respectively). One fully loaded IBM 2841 Control Unit connected with eight IBM 2321 Data Cell Devices has the capacity of 441 IBM 2311 Disk Devices, which would need to be connected to 56 IBM 2841 Control Units, which would require seven data channels. The Data Cell makes use of three concurrently operating separate seeking systems: a servo-hydraulic one to rotate the bins to select the proper subcell, and two solenoid driven ones: one to select the correct strip tab of the ten in the subcell, and the other to select one of the five head positions, for the 20 element head (100 tracks per strip). The hydraulic fluid, Mobil DTE Light, a machine tool circulating oil, is pressurized at 1500 psi and despite a lot of

folklore Folklore is shared by a particular group of people; it encompasses the traditions common to that culture, subculture or group. This includes oral traditions such as Narrative, tales, legends, proverbs and jokes. They include material culture, r ...

about oil leaks, they were very rare. The oil sump holds . Although its storage medium is tape, the 2321 is classified as a

which can directly access a record rather than scan all the tape to find a record as would a conventional tape drive. IBM's System/360 channels addressed the 2321 as a

s, i.e., a disk drive, with a 6-byte seek address of the form ØBBSCH (hexadecimal) where the first byte is zero and the remaining bytes address the Bin (i.e., cell), Bin (i.e., sub-cell), Strip, Cylinder and Head.Generically, at th
OS level
IBM defined the six bytes as BBCCHH, for Bin, Bin, Cylinder, Cylinder, Head and Head respectively.

References

External links

at Columbia University * {{ Citation , last1=Shugart , first1=Alan , last2=Tong , first2=Yang-hu , year=1966 , title=IBM 2321 data cell drive , journal=Proceedings of the April 26–28, 1966, Spring Joint Computer Conference , publisher=Association for Computing Machinery (ACM) , place=New York City, New York , pages=335–345 , url=http://portal.acm.org/citation.cfm?id=1464223 , url-access=subscription

for portions of IBM manual.
Close up photo of Data Cell drive

IBM System/360 Component Descriptions - IBM 2841 and Associated DASD
pages 65 to 72 describe the IBM 2321 2321